Summary.The amino acid composition of the muscle protein from some Swedish fishes, commonly used for food consumption has been investigated. The amino acids determined correspond to more than 90 per cent by weight of the protein. By incorporation of the alanine values obtained by other authors, more than 95 per cent of the amino acid content has been recognized. The nutritional quality of the fish protein must be classified as rather high since all the indespensable amino acids —possibly with the exception of valine — are present in amounts which corresponds to those reported to be present in rabbit‐ and human muscle protein.The writer is indebted to the Swedish Fur Breeders Corporation for their grants which supported the present investigation. He further acknowledges his thanks to Messrs Eklund and Berglund and to Mrs Ågren for their valuable assistance throughout the investi